Commutator motor



Jan. 1, 1924 1,479,160

J. SLEPIAN v COMMUTATOR MOTOR Filed OCt. 6, 1919 ISO P051 flan filmed Mach 5 WITNESSES: INVENTOR /'7// gm/ 75%;: Mall/he BY Patented Jan. 1, 1924.

UNITED STATES PATENT OFFICE.

JOSEPH SLEPIAN, OF WILKINSBURG, PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

conmcmroa moron.

Application filed October 6, 1819. Serial No. 828,808.

To all whom it may concern:

Be it known that I, JOSEPH SLEPIAN, a citizenof the United States, and a resident of Wilkinsbur in the county of Allegheny and State of ennsylvania, have invented a new and useful Improvement in Commutator Motors, of which the following is-a specification.

' My invention relates to commutator 'motors, particularly to machines of the character designated which are to be accelerated slowly, and it has for its object to provide means whereby good commutation may be obtained throughout the entire acceleration ran of the machine.

13% a better understanding of my invention, reference may be had to. the accompanying drawing in which Figure 1 is a diagrammatic view of the machines and the connections used in my commutator-motor construction; Fig. 2. is an illustration of another system embodying my invention,

and Fig. 3 is a diagrammatic chart showing the manner in WhlCh the various machine 2 elements are accelerated.

In my copending application, Serial No. 316,171 filed August 8, 1919, I have illustrated and claimed a system wherein the auxiliary dynamo-electric machines, which are associated with the main dynamo-electric machine in my 5 stem, are provided with exciting field windings which are connected in shunt relationship. I find, however, that, in some instances, it may be desirable to use auxiliary machines which are provided with series-connected field windings, and, in investigating this latter system, I have discovered. that certain novel connections, which I will hereinafter describe and claim,

40 are desirable.

eferring now more particularly to Fig. 1, a dynamo-electric machine 1 is provided with a primary member 2 and a secondary member 3, the latter being shown as rigidly connected to a' load. A source of energy here represented as a secondary member 4 of a transformer, is utilized to supply energy to the primary and secondary members of themachine 1.

Between the machine 1, and the source of supply 4 are, placed two auxiliary dynamoelectric machines, 5 and 6, provided with series-connected accelerating field windings .tion, the machine 7 and. 8, respectively, commutating-pole windings 9 and 10, respectively, commutators 11 and 12, respectively, and slip rings 13 and 14, respectivel It will be observed that the main fie d windings 7 and 8 are connected in series relationship and that, therefore, the two auxiliar machines have all of the characteristics inher-- ent in series-connected dynamo-electric ma-' and claimed in my above-mentioned co ending applica- 1 may, t rough the instrumentality of the above-described auxilia machines and connections, be accelerated at a comparatively low rate of speed, even though the auxiliary machines with which.

the commutators, functioning in the system, are mechanically connected, are 0 rated at comparatively high rates of spee As described in that application, the machines 5 and 6, if operated at equal speeds, are in-,

strumental in furnishing currents of the same frequency to both the primary and secondary members of the main machine and, therefore, the latter will not accelerate. since its speed is dependent upon the difi'erence of the auxiliary machine speeds.

However, in the system with which the present application is concerned, the auxiliary machines are provided with series-connected field windings, and, therefore, if they are operated in such manner that their speeds are equal, and, consequently, that the main or torque machine 1 isstationary, it is evident that they will function in exactly the same manner as a series-excited commutator machine, runnin under no load; that is to say, they will develop very excessive and dangerous s ds. 7

.In considering the series field windings and comprising frequency-changing paths for the power furnctions of the auxiliary machines, when provided with.

nished to the primary and secondaryl members of the torque machine, the to owing observations are pertinent. For the purposes of this discussion, l have designated the leads furnishing power to the commutator machines as A, B and C, the machine being connected to the source 4 through the leads A and C, and the machine 6 being so connected through the leads B and O.

The currents which flow through the brushes or the two auxiliary machines may be divided into two parts. One part is cancelled in the armatures of the commutator machines by the currents drawn from the slip rings thereof by the torque-machine primary and secondary members. The remaining part of the currents drawn in through the brushes is uncancelled in the armatures thereof, and, consequently, produces accelerating torque on these armatures, it should be noted, however, that both portions of these currents flow through the series-connected fields of the auxiliary machines.

At standstill oi the torque machine, the

currents which flow from the slip rings are ill?) determined entirely by the voltage between leads-A and B and leads B and C. These currents are, of course, equal, and opposite because the two members of the main torque machine l function in exactly the same mannor as a static transformer, in which the primary and secondar are substantially equal and opposite, t' e ordinary transformer magnetizing current furnishing the only reason for a discrepancy between the two currents. The corresponding parts oi the brush currents are likewise equal and opposite, and, therefore, the correspondino components of these latter currents cones in the common lead (1.

The remaining components of the brush currents, that is, those that produce acceleration oi the commutator machines, do not cancel in the common lead (l. in one of the machines they strengthen the field produced by the torque-machine currents, and in the other machine they weaken the held. in order that they shall not actually reverse the held of the latter machine, 1 have provided the store-described resistance or reactance member iii in the common lead 3,

The two commutator machines accelerate rapidly to such a speed as to reduce to zero the components ol the armature currents which are unca'ncelled by the currents drawn from slip rings. The existing fields, because of the currents drawn by the slip rings, are not reduced to zero as would be the case in ordinary series commutating ms= chines, and, therefore, the commutator me= chines, although not mechanically con= nected to their loads, are so electrically in termeshed therewith, that, as long as the torque machine requires power to run, there reverse tor machines to function as unloaded series.

excited machines.

The algebraic difference between the s eds of the two auxiliary commutator mac ines is determined by the speed of the torque machine, due to the heretofore mentioned transformer action between the two members of the latter machine, their actual speeds being determined by the currents drawn by the torque machine. The acceleration steps by which the heretofore described main torque machine ma be brought up to the various running spec s, are substantially the same as those which I have more fully described and claimed in the above-mentioned copending application, it being only necessary to so vary the speeeds of the two machines as 'to eventuate an algebraic difference which shall be equal to the torque machine speed, although I find that it ma be desirable to initially determine a sma l algebraic difference between the speeds of the two auxiliary machines during their acceleration to a speed in excess of that at which commutation diliiculties are present.

in the heretofore-described machine aggregate, l have assumed that a constant mechanical load is connected to the torque machine. inasmuch asl' find particular use for my invention in connection with railway vehicles, provision should be made whereby the system will continuevto function in a desirable manner, even though the mechanical load momentarily is withdrawn from the torque machine. Such a situation would arise, for instance, when an electrical locomotive in which my invention is embodied, is coasting down-hill, l find, moreover, that certain additional changes should be made in the fundamental system abovodescribed, in order to insure desirable o oration during regeneration or dynamic bra ing.

The system shown in Fig, 2 is one embodying my invention, and which ll find is articularly applicable for regenerative raking and for operation in which the speeds oil the commutator machines, although the latter are series-excited, are rendered inde endent of the currents drawn from the s 1p rings by the torque machine.

it will be observed that the machine 6 is no longer provided with an accelerating iield winding, and, moreover, that the two auxiliary machines are connected in series. A. small auxiliary machine .19 is energized from the source t and is belted to the machine 6, whereby the s d oi the latter may be governed indepen cntly oi the s eed oi the torque machine. It will be on 'erstood that the machine l9 is capable olE reverse rotation, and any means, such as switch it for changing the direction of held encitetion, may be employed tor this purpose.

inasmuch as the speed otthe machine it llt) may be independently determined, it is apparent that the other commutator machine will automatically assume sucha speed that the algebraic difference of the auxiliarymachine speeds will be equal to'the speed of the torque machine 1, and, moreover, it should be understood that the speed of the torque machine is determined partly by the mechanical load applied thereto and partly by the voltage AB.

To illustrate the manner in which the system shown in Fi 2 functions, reference should be had to Fig.3 which is a simplified diagrammatic chart of the interre'lationbetween the speeds of the various machine elements embodying my invention, the horizontal lines representing various positions in the acceleratin range, while the distances along these lines, such as KY and YZ, represent the full speed of the machine 6 and the machine 7 respectively, in op osito directions. Let us assume,'that goo commutation can be effected at one-third full speed of the commutator machines and thereabove.

The voltage AB is initially made small and the machine 6, which I will hereinafter designate as the fieldless machine, the machine 5 being designated as the fielded machine, is driven at one-third of its full speed. Since provision has been made whereby the speeds of the two commutator machines may be equal and yet not become dan erous, the

initial speed of the machine 6 wi 1 then become stabilized at one-third of its full speed. Upon raising the voltage applied, the torque motor starts, and, as it gains speed with theincreasing voltage, the fielded commutator machine also increases in speed. lVhen the torque motor reaches one-third of its full speed the fielded commutator machine will have reached full speed, as may be understood from a consideration of the condition shown in position 2 of Fig. 3, since the algebraic difference between a torque machine speed equal to one-third full speed nd a speed of onethird full speed existing in the fieldlesscommutator machine, is equal to full speed of the fielded commutator machine. In other words, the desirable conditions which I have heretofore pointed out as obtainable with systems of the character herein described, as well as those described in the above-mentioned copending application, have been attained as regards a slow acceleration of the main machine with a very rapid acceleration of the auxiliary machines, even though the auxiliary machines have series field-excitation characteristics which would ultimately cause them to get beyond control when their speeds should become equal if no restraining means were utilized.

The next step in the acceleration sequence, which I have here adopted for purposes of illustration, is the reversal in direction of the fieldless machine by any suitable reversing means of the driving motor thereof, and its subsequent acceleration to one-third of its full speed in a direction oppositeto that in which ithad been runnin At the same time, the speed of the fielde machine is re-1 duced to one-third full speed in the same. direction as that in which. ithad been running. The result is that the torque-machine speed is maintained constant at one-third of its full speed, as will be observed by reference to position 3 of Fig, 3.

The voltage is then raised gradually to its full value, the fieldless machine, at the same time, being gradually accelerated to its own full speed, and the changes in the torque-machine speed will be made as shown in the higher-numbered acceleration positions in Fig. 3. It will be observed,'there- -fore, that the main machine has been gradually accelerated to its full speed, and that, if need be, it can be run at a very low rate of acceleration, even though the auxiliary machines themselves and the ones in which any commutator difiiculties will be ex crienced, are operated at a speed just a ove that at which those commutation difficul ies are ap arent.

Wlii e I have shown but two embodiments of my invention'for utilizing auxiliary commutator machines provided with seriesexcited field windings, it is apparent that manymodifications of these systems may occur to those skilled in the art, and I desire, therefore, that my invention shall be limited only by the prior art or as specifically set forth in the appended claims.

I claim as my invention:

1. A dynamo-electric machine comprising primary and seconda members, and aux-- iliary single-phase dynamo-electric machines electrically associated therewith to furnish currents conductively to each of said members, the frequency of said currents being dependent upon the speeds of said auxiliary machines, at least one of said currents being polyphase currents of such nature as to produce a rotating alternating field, series exciting windings for at least one of said auxiliary machines, and means for varying the speeds of said auxiliary machines, the algebraic difference in the speeds of said auxiliary machines determining the absolute speed of said firstnamed dynamo-electric machine.

2. A dynamo-electric machine comprising primary and secondary members, auxiliary machines electrically associated therewith to' furnish currents conductively to each of said members, the frequency of said our rents being dependent upon the speeds of said auxiliary machines, at least one of said currents being polyphase currents of such nature as to produce a rotating alternating field, series exciting windings for at least Caz one of said auxiliary machines, means for varying' the speeds of said auxiliary machines, the algebraic difierence in the speeds of said auxiliary machines determining the absolute speed of said first-named dynamo electric machine, and means for preventing said auxiliary machines trons exceeding a certain predetermined speed when their speeds areequal.

3. A dynamo-electric machine comprising primary and secondary memhers, auxiliary machines electrically associated therewith to furnish currents conductively to each of said members, the frequency of said being dependent upon the speeds of said auxiliary machines,'series exciting windings for at least one of said auxiliary machines, means for varying the speeds oi. said aux iliary machines, the algebraic difference in the speeds oi said auxiliary machines de- 'termlnlng the absolute speed of said first named dynamo-electric machine, and means associated with one of said auxiliary machines to prevent its exceeding a predetermined speed When running under no-load conditions,

a. A dynamo-electric machine comprising primary and secondary members, auxiliary dynamo-electric machines electrically associated therewith to turnish currents conductively to each of said members, the ire quency of said currents being vdependent upon the speeds of said auxiliary machines,

series exciting windings for at least one of said auxiliary machines, means for varyingthe speeds ol' said auxiliary machines, the algebraic difierence in the speeds of said auxiliary machines determining the absolute speed of said first-named dynamoelectric machine, and substantially equal and opposite currents being drawn by said members through the auxiliary machines, and means in the circuit of said auxiliary machines to prevent a reversal ot the direction ot rotation at one of the mm hines,

5. ln con-ibination with a source of energy, a dynamo-electric machine comprising primary and secondary members, caniliary dynamo-electric machines connected with, and supplying substantially equal and opposite currents of varying frequencies to said primary and secondary members, as has exciting windings -for at least one of said auxiliary machines, connections between said source and the liar; cl one of said connec" ion to hoth machines, a c. last-named connection the direction or q e auxiliary machires,

6;. A dynaino-electric machine cor i mary and secondary menihcrs, chines electrically associa to tarnish substantially equal currents conductivel to said mam-hers on c neveaoo o'l machines being series excited and the other machine losing unprovided with an accelerating field Winding, and means for independently governing the speed of said last-named machine 7, A dynamo-electric machine primary and secondary memhcrs, series-connected auxiliary machines electrically assocatcd therewith to furnish substantially equal and opposite currents conduct-Lively to said members, one of said machines series excited and the other machine unprovided with an accelerating field Winding, and means for independently governing the speed of said last-named machine.

8. The method of operating a dynamoelectric machine comprising primary and secondary members, each conductively sapplied with power from auxiliary machines electrically associated therewith, the latter lacing energized from a variable source ct electromotive force, Which comprises runing one of the auxiliary machines at a predetermined speed, irrespective of the voltage applied thereto, and feeding one member of the main dynamo-electric machine therefrom, the speed of the other auxiliary ma chine being determined by the magnetic action between the primary and secondary memhers oi the main dynamo-electric ma chine,

9. The method of operating a dynamoelectric machine comprising primary and secondary members each conductively sup plied with power from series-connected auxiliary machines electrically associated therewith, the latter hcingenergiaed from a variable source or electromotive torce, which comprises running one of the auxiliary ma chines at a predetermined speed, irrespective of the voltage applied thereto, and feeding one memher' of the main dynamo-electric machine therefrom, the speed of the other auxiliary machine being determined by the magnetic action between the: primary and secondary members of the main dynamo electric machine, and then varying the volt-= age applied to said auxiliary machines, While maintaining; the speed ct one of the auxiliary machines constant, Wherehy the speed oi the main dynamo-electric machine increased it), method of a electric machine comprisi g condary memhers conduct-lively d with ovve coin :unnir chines at a predetern at, of the applie iereto, W one member or the dc ne there'lrom, the

auxiliary" machine losing determin he o ed hy ltlti electric machine comprising primary and magnetic action between the primary and secondary members of the main dynamoelectric machine, then varying the voltage applied to said auxiliary machines, while maintaining the speed of one of the auxiliary machines constant, whereby the speed of the main dynamo-electric machine isin-- creased, and then reducin the speed of the last-named auxiliary mac ine to zero and reversing its direction of rotation at the same time that the speed of the other auxiliary machine is reduced, the speed of the main dynamo-electric machine remaining constant during the latter adjustment of the auxiliary dynamo-electric machines.

11. The method of operating a dynamosecondary members each conductively supplied with power from series-connected auxlliary machines electrically associated therewith, the latter being energized from a variable source of electromotive force, which comprises running one of the auxiliary machines at a predetermined speed, irrespective of the volta e ap lied thereto, while feeding one mem er of the main (1 namoelectric machine therefrom, the s e of the other auxiliary machine being etermined by the ma etic action between the rimaryand secon ary members of the main ynamoelectric machine being determined by the magnetic action between the primary and secondary members of the main dynamoelectric machine, then varying the volt e applied to said auxiliary machines whi e maintaining the speed of'one of the auxiliary machines constant, whereby the speed of the main dynamo-electric machine is increased, then reducing the speed of the lastnamed auxiliary machine to zero and reversing its direction of rotation at the same time that the speed of the other auxiliary ma chine is reduced, the speed of the main dynamo-electric machine remaining constant during the latter adjustment of the auxiliary dynamo-electric machines, and finally runnin the independently-regulated machine at ull speed and a plying full voltage to the series-connecte aux liary machines, whereby the main machine is operated at full speed.

In testimony whereof, I have hereunto subscribed my name this 30th day of Sept. 1919. v

JOSEPH 'SLEPIAN. 

